xref: /openbmc/linux/sound/core/oss/pcm_plugin.c (revision 64c70b1c)
1 /*
2  *  PCM Plug-In shared (kernel/library) code
3  *  Copyright (c) 1999 by Jaroslav Kysela <perex@suse.cz>
4  *  Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
5  *
6  *
7  *   This library is free software; you can redistribute it and/or modify
8  *   it under the terms of the GNU Library General Public License as
9  *   published by the Free Software Foundation; either version 2 of
10  *   the License, or (at your option) any later version.
11  *
12  *   This program is distributed in the hope that it will be useful,
13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  *   GNU Library General Public License for more details.
16  *
17  *   You should have received a copy of the GNU Library General Public
18  *   License along with this library; if not, write to the Free Software
19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
20  *
21  */
22 
23 #if 0
24 #define PLUGIN_DEBUG
25 #endif
26 
27 #include <sound/driver.h>
28 
29 #ifdef CONFIG_SND_PCM_OSS_PLUGINS
30 
31 #include <linux/slab.h>
32 #include <linux/time.h>
33 #include <linux/vmalloc.h>
34 #include <sound/core.h>
35 #include <sound/pcm.h>
36 #include <sound/pcm_params.h>
37 #include "pcm_plugin.h"
38 
39 #define snd_pcm_plug_first(plug) ((plug)->runtime->oss.plugin_first)
40 #define snd_pcm_plug_last(plug) ((plug)->runtime->oss.plugin_last)
41 
42 /*
43  *  because some cards might have rates "very close", we ignore
44  *  all "resampling" requests within +-5%
45  */
46 static int rate_match(unsigned int src_rate, unsigned int dst_rate)
47 {
48 	unsigned int low = (src_rate * 95) / 100;
49 	unsigned int high = (src_rate * 105) / 100;
50 	return dst_rate >= low && dst_rate <= high;
51 }
52 
53 static int snd_pcm_plugin_alloc(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames)
54 {
55 	struct snd_pcm_plugin_format *format;
56 	ssize_t width;
57 	size_t size;
58 	unsigned int channel;
59 	struct snd_pcm_plugin_channel *c;
60 
61 	if (plugin->stream == SNDRV_PCM_STREAM_PLAYBACK) {
62 		format = &plugin->src_format;
63 	} else {
64 		format = &plugin->dst_format;
65 	}
66 	if ((width = snd_pcm_format_physical_width(format->format)) < 0)
67 		return width;
68 	size = frames * format->channels * width;
69 	snd_assert((size % 8) == 0, return -ENXIO);
70 	size /= 8;
71 	if (plugin->buf_frames < frames) {
72 		vfree(plugin->buf);
73 		plugin->buf = vmalloc(size);
74 		plugin->buf_frames = frames;
75 	}
76 	if (!plugin->buf) {
77 		plugin->buf_frames = 0;
78 		return -ENOMEM;
79 	}
80 	c = plugin->buf_channels;
81 	if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
82 		for (channel = 0; channel < format->channels; channel++, c++) {
83 			c->frames = frames;
84 			c->enabled = 1;
85 			c->wanted = 0;
86 			c->area.addr = plugin->buf;
87 			c->area.first = channel * width;
88 			c->area.step = format->channels * width;
89 		}
90 	} else if (plugin->access == SNDRV_PCM_ACCESS_RW_NONINTERLEAVED) {
91 		snd_assert((size % format->channels) == 0,);
92 		size /= format->channels;
93 		for (channel = 0; channel < format->channels; channel++, c++) {
94 			c->frames = frames;
95 			c->enabled = 1;
96 			c->wanted = 0;
97 			c->area.addr = plugin->buf + (channel * size);
98 			c->area.first = 0;
99 			c->area.step = width;
100 		}
101 	} else
102 		return -EINVAL;
103 	return 0;
104 }
105 
106 int snd_pcm_plug_alloc(struct snd_pcm_substream *plug, snd_pcm_uframes_t frames)
107 {
108 	int err;
109 	snd_assert(snd_pcm_plug_first(plug) != NULL, return -ENXIO);
110 	if (snd_pcm_plug_stream(plug) == SNDRV_PCM_STREAM_PLAYBACK) {
111 		struct snd_pcm_plugin *plugin = snd_pcm_plug_first(plug);
112 		while (plugin->next) {
113 			if (plugin->dst_frames)
114 				frames = plugin->dst_frames(plugin, frames);
115 			snd_assert(frames > 0, return -ENXIO);
116 			plugin = plugin->next;
117 			err = snd_pcm_plugin_alloc(plugin, frames);
118 			if (err < 0)
119 				return err;
120 		}
121 	} else {
122 		struct snd_pcm_plugin *plugin = snd_pcm_plug_last(plug);
123 		while (plugin->prev) {
124 			if (plugin->src_frames)
125 				frames = plugin->src_frames(plugin, frames);
126 			snd_assert(frames > 0, return -ENXIO);
127 			plugin = plugin->prev;
128 			err = snd_pcm_plugin_alloc(plugin, frames);
129 			if (err < 0)
130 				return err;
131 		}
132 	}
133 	return 0;
134 }
135 
136 
137 snd_pcm_sframes_t snd_pcm_plugin_client_channels(struct snd_pcm_plugin *plugin,
138 				       snd_pcm_uframes_t frames,
139 				       struct snd_pcm_plugin_channel **channels)
140 {
141 	*channels = plugin->buf_channels;
142 	return frames;
143 }
144 
145 int snd_pcm_plugin_build(struct snd_pcm_substream *plug,
146 			 const char *name,
147 			 struct snd_pcm_plugin_format *src_format,
148 			 struct snd_pcm_plugin_format *dst_format,
149 			 size_t extra,
150 			 struct snd_pcm_plugin **ret)
151 {
152 	struct snd_pcm_plugin *plugin;
153 	unsigned int channels;
154 
155 	snd_assert(plug != NULL, return -ENXIO);
156 	snd_assert(src_format != NULL && dst_format != NULL, return -ENXIO);
157 	plugin = kzalloc(sizeof(*plugin) + extra, GFP_KERNEL);
158 	if (plugin == NULL)
159 		return -ENOMEM;
160 	plugin->name = name;
161 	plugin->plug = plug;
162 	plugin->stream = snd_pcm_plug_stream(plug);
163 	plugin->access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
164 	plugin->src_format = *src_format;
165 	plugin->src_width = snd_pcm_format_physical_width(src_format->format);
166 	snd_assert(plugin->src_width > 0, );
167 	plugin->dst_format = *dst_format;
168 	plugin->dst_width = snd_pcm_format_physical_width(dst_format->format);
169 	snd_assert(plugin->dst_width > 0, );
170 	if (plugin->stream == SNDRV_PCM_STREAM_PLAYBACK)
171 		channels = src_format->channels;
172 	else
173 		channels = dst_format->channels;
174 	plugin->buf_channels = kcalloc(channels, sizeof(*plugin->buf_channels), GFP_KERNEL);
175 	if (plugin->buf_channels == NULL) {
176 		snd_pcm_plugin_free(plugin);
177 		return -ENOMEM;
178 	}
179 	plugin->client_channels = snd_pcm_plugin_client_channels;
180 	*ret = plugin;
181 	return 0;
182 }
183 
184 int snd_pcm_plugin_free(struct snd_pcm_plugin *plugin)
185 {
186 	if (! plugin)
187 		return 0;
188 	if (plugin->private_free)
189 		plugin->private_free(plugin);
190 	kfree(plugin->buf_channels);
191 	vfree(plugin->buf);
192 	kfree(plugin);
193 	return 0;
194 }
195 
196 snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *plug, snd_pcm_uframes_t drv_frames)
197 {
198 	struct snd_pcm_plugin *plugin, *plugin_prev, *plugin_next;
199 	int stream = snd_pcm_plug_stream(plug);
200 
201 	snd_assert(plug != NULL, return -ENXIO);
202 	if (drv_frames == 0)
203 		return 0;
204 	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
205 		plugin = snd_pcm_plug_last(plug);
206 		while (plugin && drv_frames > 0) {
207 			plugin_prev = plugin->prev;
208 			if (plugin->src_frames)
209 				drv_frames = plugin->src_frames(plugin, drv_frames);
210 			plugin = plugin_prev;
211 		}
212 	} else if (stream == SNDRV_PCM_STREAM_CAPTURE) {
213 		plugin = snd_pcm_plug_first(plug);
214 		while (plugin && drv_frames > 0) {
215 			plugin_next = plugin->next;
216 			if (plugin->dst_frames)
217 				drv_frames = plugin->dst_frames(plugin, drv_frames);
218 			plugin = plugin_next;
219 		}
220 	} else
221 		snd_BUG();
222 	return drv_frames;
223 }
224 
225 snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *plug, snd_pcm_uframes_t clt_frames)
226 {
227 	struct snd_pcm_plugin *plugin, *plugin_prev, *plugin_next;
228 	snd_pcm_sframes_t frames;
229 	int stream = snd_pcm_plug_stream(plug);
230 
231 	snd_assert(plug != NULL, return -ENXIO);
232 	if (clt_frames == 0)
233 		return 0;
234 	frames = clt_frames;
235 	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
236 		plugin = snd_pcm_plug_first(plug);
237 		while (plugin && frames > 0) {
238 			plugin_next = plugin->next;
239 			if (plugin->dst_frames) {
240 				frames = plugin->dst_frames(plugin, frames);
241 				if (frames < 0)
242 					return frames;
243 			}
244 			plugin = plugin_next;
245 		}
246 	} else if (stream == SNDRV_PCM_STREAM_CAPTURE) {
247 		plugin = snd_pcm_plug_last(plug);
248 		while (plugin) {
249 			plugin_prev = plugin->prev;
250 			if (plugin->src_frames) {
251 				frames = plugin->src_frames(plugin, frames);
252 				if (frames < 0)
253 					return frames;
254 			}
255 			plugin = plugin_prev;
256 		}
257 	} else
258 		snd_BUG();
259 	return frames;
260 }
261 
262 static int snd_pcm_plug_formats(struct snd_mask *mask, int format)
263 {
264 	struct snd_mask formats = *mask;
265 	u64 linfmts = (SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S8 |
266 		       SNDRV_PCM_FMTBIT_U16_LE | SNDRV_PCM_FMTBIT_S16_LE |
267 		       SNDRV_PCM_FMTBIT_U16_BE | SNDRV_PCM_FMTBIT_S16_BE |
268 		       SNDRV_PCM_FMTBIT_U24_LE | SNDRV_PCM_FMTBIT_S24_LE |
269 		       SNDRV_PCM_FMTBIT_U24_BE | SNDRV_PCM_FMTBIT_S24_BE |
270 		       SNDRV_PCM_FMTBIT_U32_LE | SNDRV_PCM_FMTBIT_S32_LE |
271 		       SNDRV_PCM_FMTBIT_U32_BE | SNDRV_PCM_FMTBIT_S32_BE);
272 	snd_mask_set(&formats, SNDRV_PCM_FORMAT_MU_LAW);
273 
274 	if (formats.bits[0] & (u32)linfmts)
275 		formats.bits[0] |= (u32)linfmts;
276 	if (formats.bits[1] & (u32)(linfmts >> 32))
277 		formats.bits[1] |= (u32)(linfmts >> 32);
278 	return snd_mask_test(&formats, format);
279 }
280 
281 static int preferred_formats[] = {
282 	SNDRV_PCM_FORMAT_S16_LE,
283 	SNDRV_PCM_FORMAT_S16_BE,
284 	SNDRV_PCM_FORMAT_U16_LE,
285 	SNDRV_PCM_FORMAT_U16_BE,
286 	SNDRV_PCM_FORMAT_S24_LE,
287 	SNDRV_PCM_FORMAT_S24_BE,
288 	SNDRV_PCM_FORMAT_U24_LE,
289 	SNDRV_PCM_FORMAT_U24_BE,
290 	SNDRV_PCM_FORMAT_S32_LE,
291 	SNDRV_PCM_FORMAT_S32_BE,
292 	SNDRV_PCM_FORMAT_U32_LE,
293 	SNDRV_PCM_FORMAT_U32_BE,
294 	SNDRV_PCM_FORMAT_S8,
295 	SNDRV_PCM_FORMAT_U8
296 };
297 
298 int snd_pcm_plug_slave_format(int format, struct snd_mask *format_mask)
299 {
300 	if (snd_mask_test(format_mask, format))
301 		return format;
302 	if (! snd_pcm_plug_formats(format_mask, format))
303 		return -EINVAL;
304 	if (snd_pcm_format_linear(format)) {
305 		int width = snd_pcm_format_width(format);
306 		int unsignd = snd_pcm_format_unsigned(format);
307 		int big = snd_pcm_format_big_endian(format);
308 		int format1;
309 		int wid, width1=width;
310 		int dwidth1 = 8;
311 		for (wid = 0; wid < 4; ++wid) {
312 			int end, big1 = big;
313 			for (end = 0; end < 2; ++end) {
314 				int sgn, unsignd1 = unsignd;
315 				for (sgn = 0; sgn < 2; ++sgn) {
316 					format1 = snd_pcm_build_linear_format(width1, unsignd1, big1);
317 					if (format1 >= 0 &&
318 					    snd_mask_test(format_mask, format1))
319 						goto _found;
320 					unsignd1 = !unsignd1;
321 				}
322 				big1 = !big1;
323 			}
324 			if (width1 == 32) {
325 				dwidth1 = -dwidth1;
326 				width1 = width;
327 			}
328 			width1 += dwidth1;
329 		}
330 		return -EINVAL;
331 	_found:
332 		return format1;
333 	} else {
334 		unsigned int i;
335 		switch (format) {
336 		case SNDRV_PCM_FORMAT_MU_LAW:
337 			for (i = 0; i < ARRAY_SIZE(preferred_formats); ++i) {
338 				int format1 = preferred_formats[i];
339 				if (snd_mask_test(format_mask, format1))
340 					return format1;
341 			}
342 		default:
343 			return -EINVAL;
344 		}
345 	}
346 }
347 
348 int snd_pcm_plug_format_plugins(struct snd_pcm_substream *plug,
349 				struct snd_pcm_hw_params *params,
350 				struct snd_pcm_hw_params *slave_params)
351 {
352 	struct snd_pcm_plugin_format tmpformat;
353 	struct snd_pcm_plugin_format dstformat;
354 	struct snd_pcm_plugin_format srcformat;
355 	int src_access, dst_access;
356 	struct snd_pcm_plugin *plugin = NULL;
357 	int err;
358 	int stream = snd_pcm_plug_stream(plug);
359 	int slave_interleaved = (params_channels(slave_params) == 1 ||
360 				 params_access(slave_params) == SNDRV_PCM_ACCESS_RW_INTERLEAVED);
361 
362 	switch (stream) {
363 	case SNDRV_PCM_STREAM_PLAYBACK:
364 		dstformat.format = params_format(slave_params);
365 		dstformat.rate = params_rate(slave_params);
366 		dstformat.channels = params_channels(slave_params);
367 		srcformat.format = params_format(params);
368 		srcformat.rate = params_rate(params);
369 		srcformat.channels = params_channels(params);
370 		src_access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
371 		dst_access = (slave_interleaved ? SNDRV_PCM_ACCESS_RW_INTERLEAVED :
372 						  SNDRV_PCM_ACCESS_RW_NONINTERLEAVED);
373 		break;
374 	case SNDRV_PCM_STREAM_CAPTURE:
375 		dstformat.format = params_format(params);
376 		dstformat.rate = params_rate(params);
377 		dstformat.channels = params_channels(params);
378 		srcformat.format = params_format(slave_params);
379 		srcformat.rate = params_rate(slave_params);
380 		srcformat.channels = params_channels(slave_params);
381 		src_access = (slave_interleaved ? SNDRV_PCM_ACCESS_RW_INTERLEAVED :
382 						  SNDRV_PCM_ACCESS_RW_NONINTERLEAVED);
383 		dst_access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
384 		break;
385 	default:
386 		snd_BUG();
387 		return -EINVAL;
388 	}
389 	tmpformat = srcformat;
390 
391 	pdprintf("srcformat: format=%i, rate=%i, channels=%i\n",
392 		 srcformat.format,
393 		 srcformat.rate,
394 		 srcformat.channels);
395 	pdprintf("dstformat: format=%i, rate=%i, channels=%i\n",
396 		 dstformat.format,
397 		 dstformat.rate,
398 		 dstformat.channels);
399 
400 	/* Format change (linearization) */
401 	if (! rate_match(srcformat.rate, dstformat.rate) &&
402 	    ! snd_pcm_format_linear(srcformat.format)) {
403 		if (srcformat.format != SNDRV_PCM_FORMAT_MU_LAW)
404 			return -EINVAL;
405 		tmpformat.format = SNDRV_PCM_FORMAT_S16;
406 		err = snd_pcm_plugin_build_mulaw(plug,
407 						 &srcformat, &tmpformat,
408 						 &plugin);
409 		if (err < 0)
410 			return err;
411 		err = snd_pcm_plugin_append(plugin);
412 		if (err < 0) {
413 			snd_pcm_plugin_free(plugin);
414 			return err;
415 		}
416 		srcformat = tmpformat;
417 		src_access = dst_access;
418 	}
419 
420 	/* channels reduction */
421 	if (srcformat.channels > dstformat.channels) {
422 		tmpformat.channels = dstformat.channels;
423 		err = snd_pcm_plugin_build_route(plug, &srcformat, &tmpformat, &plugin);
424 		pdprintf("channels reduction: src=%i, dst=%i returns %i\n", srcformat.channels, tmpformat.channels, err);
425 		if (err < 0)
426 			return err;
427 		err = snd_pcm_plugin_append(plugin);
428 		if (err < 0) {
429 			snd_pcm_plugin_free(plugin);
430 			return err;
431 		}
432 		srcformat = tmpformat;
433 		src_access = dst_access;
434 	}
435 
436 	/* rate resampling */
437 	if (!rate_match(srcformat.rate, dstformat.rate)) {
438 		if (srcformat.format != SNDRV_PCM_FORMAT_S16) {
439 			/* convert to S16 for resampling */
440 			tmpformat.format = SNDRV_PCM_FORMAT_S16;
441 			err = snd_pcm_plugin_build_linear(plug,
442 							  &srcformat, &tmpformat,
443 							  &plugin);
444 			if (err < 0)
445 				return err;
446 			err = snd_pcm_plugin_append(plugin);
447 			if (err < 0) {
448 				snd_pcm_plugin_free(plugin);
449 				return err;
450 			}
451 			srcformat = tmpformat;
452 			src_access = dst_access;
453 		}
454 		tmpformat.rate = dstformat.rate;
455         	err = snd_pcm_plugin_build_rate(plug,
456         					&srcformat, &tmpformat,
457 						&plugin);
458 		pdprintf("rate down resampling: src=%i, dst=%i returns %i\n", srcformat.rate, tmpformat.rate, err);
459 		if (err < 0)
460 			return err;
461 		err = snd_pcm_plugin_append(plugin);
462 		if (err < 0) {
463 			snd_pcm_plugin_free(plugin);
464 			return err;
465 		}
466 		srcformat = tmpformat;
467 		src_access = dst_access;
468         }
469 
470 	/* format change */
471 	if (srcformat.format != dstformat.format) {
472 		tmpformat.format = dstformat.format;
473 		if (srcformat.format == SNDRV_PCM_FORMAT_MU_LAW ||
474 		    tmpformat.format == SNDRV_PCM_FORMAT_MU_LAW) {
475 			err = snd_pcm_plugin_build_mulaw(plug,
476 							 &srcformat, &tmpformat,
477 							 &plugin);
478 		}
479 		else if (snd_pcm_format_linear(srcformat.format) &&
480 			 snd_pcm_format_linear(tmpformat.format)) {
481 			err = snd_pcm_plugin_build_linear(plug,
482 							  &srcformat, &tmpformat,
483 							  &plugin);
484 		}
485 		else
486 			return -EINVAL;
487 		pdprintf("format change: src=%i, dst=%i returns %i\n", srcformat.format, tmpformat.format, err);
488 		if (err < 0)
489 			return err;
490 		err = snd_pcm_plugin_append(plugin);
491 		if (err < 0) {
492 			snd_pcm_plugin_free(plugin);
493 			return err;
494 		}
495 		srcformat = tmpformat;
496 		src_access = dst_access;
497 	}
498 
499 	/* channels extension */
500 	if (srcformat.channels < dstformat.channels) {
501 		tmpformat.channels = dstformat.channels;
502 		err = snd_pcm_plugin_build_route(plug, &srcformat, &tmpformat, &plugin);
503 		pdprintf("channels extension: src=%i, dst=%i returns %i\n", srcformat.channels, tmpformat.channels, err);
504 		if (err < 0)
505 			return err;
506 		err = snd_pcm_plugin_append(plugin);
507 		if (err < 0) {
508 			snd_pcm_plugin_free(plugin);
509 			return err;
510 		}
511 		srcformat = tmpformat;
512 		src_access = dst_access;
513 	}
514 
515 	/* de-interleave */
516 	if (src_access != dst_access) {
517 		err = snd_pcm_plugin_build_copy(plug,
518 						&srcformat,
519 						&tmpformat,
520 						&plugin);
521 		pdprintf("interleave change (copy: returns %i)\n", err);
522 		if (err < 0)
523 			return err;
524 		err = snd_pcm_plugin_append(plugin);
525 		if (err < 0) {
526 			snd_pcm_plugin_free(plugin);
527 			return err;
528 		}
529 	}
530 
531 	return 0;
532 }
533 
534 snd_pcm_sframes_t snd_pcm_plug_client_channels_buf(struct snd_pcm_substream *plug,
535 					 char *buf,
536 					 snd_pcm_uframes_t count,
537 					 struct snd_pcm_plugin_channel **channels)
538 {
539 	struct snd_pcm_plugin *plugin;
540 	struct snd_pcm_plugin_channel *v;
541 	struct snd_pcm_plugin_format *format;
542 	int width, nchannels, channel;
543 	int stream = snd_pcm_plug_stream(plug);
544 
545 	snd_assert(buf != NULL, return -ENXIO);
546 	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
547 		plugin = snd_pcm_plug_first(plug);
548 		format = &plugin->src_format;
549 	} else {
550 		plugin = snd_pcm_plug_last(plug);
551 		format = &plugin->dst_format;
552 	}
553 	v = plugin->buf_channels;
554 	*channels = v;
555 	if ((width = snd_pcm_format_physical_width(format->format)) < 0)
556 		return width;
557 	nchannels = format->channels;
558 	snd_assert(plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED || format->channels <= 1, return -ENXIO);
559 	for (channel = 0; channel < nchannels; channel++, v++) {
560 		v->frames = count;
561 		v->enabled = 1;
562 		v->wanted = (stream == SNDRV_PCM_STREAM_CAPTURE);
563 		v->area.addr = buf;
564 		v->area.first = channel * width;
565 		v->area.step = nchannels * width;
566 	}
567 	return count;
568 }
569 
570 snd_pcm_sframes_t snd_pcm_plug_write_transfer(struct snd_pcm_substream *plug, struct snd_pcm_plugin_channel *src_channels, snd_pcm_uframes_t size)
571 {
572 	struct snd_pcm_plugin *plugin, *next;
573 	struct snd_pcm_plugin_channel *dst_channels;
574 	int err;
575 	snd_pcm_sframes_t frames = size;
576 
577 	plugin = snd_pcm_plug_first(plug);
578 	while (plugin && frames > 0) {
579 		if ((next = plugin->next) != NULL) {
580 			snd_pcm_sframes_t frames1 = frames;
581 			if (plugin->dst_frames)
582 				frames1 = plugin->dst_frames(plugin, frames);
583 			if ((err = next->client_channels(next, frames1, &dst_channels)) < 0) {
584 				return err;
585 			}
586 			if (err != frames1) {
587 				frames = err;
588 				if (plugin->src_frames)
589 					frames = plugin->src_frames(plugin, frames1);
590 			}
591 		} else
592 			dst_channels = NULL;
593 		pdprintf("write plugin: %s, %li\n", plugin->name, frames);
594 		if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
595 			return frames;
596 		src_channels = dst_channels;
597 		plugin = next;
598 	}
599 	return snd_pcm_plug_client_size(plug, frames);
600 }
601 
602 snd_pcm_sframes_t snd_pcm_plug_read_transfer(struct snd_pcm_substream *plug, struct snd_pcm_plugin_channel *dst_channels_final, snd_pcm_uframes_t size)
603 {
604 	struct snd_pcm_plugin *plugin, *next;
605 	struct snd_pcm_plugin_channel *src_channels, *dst_channels;
606 	snd_pcm_sframes_t frames = size;
607 	int err;
608 
609 	frames = snd_pcm_plug_slave_size(plug, frames);
610 	if (frames < 0)
611 		return frames;
612 
613 	src_channels = NULL;
614 	plugin = snd_pcm_plug_first(plug);
615 	while (plugin && frames > 0) {
616 		if ((next = plugin->next) != NULL) {
617 			if ((err = plugin->client_channels(plugin, frames, &dst_channels)) < 0) {
618 				return err;
619 			}
620 			frames = err;
621 		} else {
622 			dst_channels = dst_channels_final;
623 		}
624 		pdprintf("read plugin: %s, %li\n", plugin->name, frames);
625 		if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
626 			return frames;
627 		plugin = next;
628 		src_channels = dst_channels;
629 	}
630 	return frames;
631 }
632 
633 int snd_pcm_area_silence(const struct snd_pcm_channel_area *dst_area, size_t dst_offset,
634 			 size_t samples, int format)
635 {
636 	/* FIXME: sub byte resolution and odd dst_offset */
637 	unsigned char *dst;
638 	unsigned int dst_step;
639 	int width;
640 	const unsigned char *silence;
641 	if (!dst_area->addr)
642 		return 0;
643 	dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
644 	width = snd_pcm_format_physical_width(format);
645 	if (width <= 0)
646 		return -EINVAL;
647 	if (dst_area->step == (unsigned int) width && width >= 8)
648 		return snd_pcm_format_set_silence(format, dst, samples);
649 	silence = snd_pcm_format_silence_64(format);
650 	if (! silence)
651 		return -EINVAL;
652 	dst_step = dst_area->step / 8;
653 	if (width == 4) {
654 		/* Ima ADPCM */
655 		int dstbit = dst_area->first % 8;
656 		int dstbit_step = dst_area->step % 8;
657 		while (samples-- > 0) {
658 			if (dstbit)
659 				*dst &= 0xf0;
660 			else
661 				*dst &= 0x0f;
662 			dst += dst_step;
663 			dstbit += dstbit_step;
664 			if (dstbit == 8) {
665 				dst++;
666 				dstbit = 0;
667 			}
668 		}
669 	} else {
670 		width /= 8;
671 		while (samples-- > 0) {
672 			memcpy(dst, silence, width);
673 			dst += dst_step;
674 		}
675 	}
676 	return 0;
677 }
678 
679 int snd_pcm_area_copy(const struct snd_pcm_channel_area *src_area, size_t src_offset,
680 		      const struct snd_pcm_channel_area *dst_area, size_t dst_offset,
681 		      size_t samples, int format)
682 {
683 	/* FIXME: sub byte resolution and odd dst_offset */
684 	char *src, *dst;
685 	int width;
686 	int src_step, dst_step;
687 	src = src_area->addr + (src_area->first + src_area->step * src_offset) / 8;
688 	if (!src_area->addr)
689 		return snd_pcm_area_silence(dst_area, dst_offset, samples, format);
690 	dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
691 	if (!dst_area->addr)
692 		return 0;
693 	width = snd_pcm_format_physical_width(format);
694 	if (width <= 0)
695 		return -EINVAL;
696 	if (src_area->step == (unsigned int) width &&
697 	    dst_area->step == (unsigned int) width && width >= 8) {
698 		size_t bytes = samples * width / 8;
699 		memcpy(dst, src, bytes);
700 		return 0;
701 	}
702 	src_step = src_area->step / 8;
703 	dst_step = dst_area->step / 8;
704 	if (width == 4) {
705 		/* Ima ADPCM */
706 		int srcbit = src_area->first % 8;
707 		int srcbit_step = src_area->step % 8;
708 		int dstbit = dst_area->first % 8;
709 		int dstbit_step = dst_area->step % 8;
710 		while (samples-- > 0) {
711 			unsigned char srcval;
712 			if (srcbit)
713 				srcval = *src & 0x0f;
714 			else
715 				srcval = (*src & 0xf0) >> 4;
716 			if (dstbit)
717 				*dst = (*dst & 0xf0) | srcval;
718 			else
719 				*dst = (*dst & 0x0f) | (srcval << 4);
720 			src += src_step;
721 			srcbit += srcbit_step;
722 			if (srcbit == 8) {
723 				src++;
724 				srcbit = 0;
725 			}
726 			dst += dst_step;
727 			dstbit += dstbit_step;
728 			if (dstbit == 8) {
729 				dst++;
730 				dstbit = 0;
731 			}
732 		}
733 	} else {
734 		width /= 8;
735 		while (samples-- > 0) {
736 			memcpy(dst, src, width);
737 			src += src_step;
738 			dst += dst_step;
739 		}
740 	}
741 	return 0;
742 }
743 
744 #endif
745